// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
 *******************************************************************************
 * Copyright (C) 2012-2014, International Business Machines Corporation and    *
 * others. All Rights Reserved.                                                *
 *******************************************************************************
 */
package com.ibm.icu.util;

import com.ibm.icu.util.ULocale.Category;
import java.util.Date;

/**
 * <code>DangiCalendar</code> is a concrete subclass of {@link Calendar} that implements a
 * traditional Korean calendar.
 *
 * @internal
 * @deprecated This API is ICU internal only.
 */
@Deprecated
public class DangiCalendar extends ChineseCalendar {

    private static final long serialVersionUID = 8156297445349501985L;

    /**
     * The time zone used for performing astronomical computations for Dangi calendar. In Korea
     * various timezones have been used historically (cf.
     * http://www.math.snu.ac.kr/~kye/others/lunar.html):
     *
     * <p>- 1908/04/01: GMT+8 1908/04/01 - 1911/12/31: GMT+8.5 1912/01/01 - 1954/03/20: GMT+9
     * 1954/03/21 - 1961/08/09: GMT+8.5 1961/08/10 - : GMT+9
     *
     * <p>Note that, in 1908-1911, the government did not apply the timezone change but used GMT+8.
     * In addition, 1954-1961's timezone change does not affect the lunar date calculation.
     * Therefore, the following simpler rule works:
     *
     * <p>-1911: GMT+8 1912-: GMT+9
     *
     * <p>Unfortunately, our astronomer's approximation doesn't agree with the references
     * (http://www.math.snu.ac.kr/~kye/others/lunar.html and
     * http://astro.kasi.re.kr/Life/ConvertSolarLunarForm.aspx?MenuID=115) in 1897/7/30. So the
     * following ad hoc fix is used here:
     *
     * <p>-1896: GMT+8 1897: GMT+7 1898-1911: GMT+8 1912- : GMT+9
     */
    private static final TimeZone KOREA_ZONE;

    static {
        InitialTimeZoneRule initialTimeZone = new InitialTimeZoneRule("GMT+8", 8 * ONE_HOUR, 0);
        long[] millis1897 = {
            (1897 - 1970) * 365L * ONE_DAY
        }; // some days of error is not a problem here
        long[] millis1898 = {
            (1898 - 1970) * 365L * ONE_DAY
        }; // some days of error is not a problem here
        long[] millis1912 = {
            (1912 - 1970) * 365L * ONE_DAY
        }; // this doesn't create an issue for 1911/12/20
        TimeZoneRule rule1897 =
                new TimeArrayTimeZoneRule(
                        "Korean 1897", 7 * ONE_HOUR, 0, millis1897, DateTimeRule.STANDARD_TIME);
        TimeZoneRule rule1898to1911 =
                new TimeArrayTimeZoneRule(
                        "Korean 1898-1911",
                        8 * ONE_HOUR,
                        0,
                        millis1898,
                        DateTimeRule.STANDARD_TIME);
        TimeZoneRule ruleFrom1912 =
                new TimeArrayTimeZoneRule(
                        "Korean 1912-", 9 * ONE_HOUR, 0, millis1912, DateTimeRule.STANDARD_TIME);

        RuleBasedTimeZone tz = new RuleBasedTimeZone("KOREA_ZONE", initialTimeZone);
        tz.addTransitionRule(rule1897);
        tz.addTransitionRule(rule1898to1911);
        tz.addTransitionRule(ruleFrom1912);
        tz.freeze();
        KOREA_ZONE = tz;
    }
    ;

    /**
     * Construct a <code>DangiCalendar</code> with the default time zone and locale.
     *
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    public DangiCalendar() {
        this(TimeZone.getDefault(), ULocale.getDefault(Category.FORMAT));
    }

    /**
     * Construct a <code>DangiCalendar</code> with the give date set in the default time zone with
     * the default locale.
     *
     * @param date The date to which the new calendar is set.
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    public DangiCalendar(Date date) {
        this(TimeZone.getDefault(), ULocale.getDefault(Category.FORMAT));
        setTime(date);
    }

    /**
     * Construct a <code>DangiCalendar</code> based on the current time with the given time zone
     * with the given locale.
     *
     * @param zone the given time zone
     * @param locale the given locale
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    public DangiCalendar(TimeZone zone, ULocale locale) {
        super(zone, locale, KOREA_ZONE);
    }

    /**
     * {@inheritDoc}
     *
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Override
    @Deprecated
    public String getType() {
        return "dangi";
    }
}
